Suction table roll



April 15, 1930.

H. R. FARNSWORTH SUCTION TABLE ROLL Filed March 26, 1928 2 'Sheets-Sheet l IN VEN TOR.

A TTORNEYS.

April 15, 1930. H. R. FARNswQRTH 1,754,822

SUCTION TABLE ROLL Filed March 26, 1928 2 Sheets-Sheet 2 "mgm/2 INVENTOR.

A TTORN E YS.

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tildilt'tl, dbltbltlllt 'T0 THE ldll di; TEXTILE @than till' tllUl'lK'Y, OHIO The present invention relates to suction .rolls for paper melting machines and more particularly the smaller diameter rolls auch as table and guide rolls. Y

lt is not intended to replace the table rolls by such small diameter rollsu ylhrr-:y will be retained on their regular positions and operate as usual. llt is for -conrparative diameters and relative positions in the inachine that they are referred to.,

lt will be understood that the invention is to be applied to and used as a part ofthe regun lar standard Fourdrinier wet end., Preferably, one or more of the rollt hereinafter described, will be put in place of .and substituted `for a corresponding number of flat boites..

lor inany years it has been considered that .the wet web of' pulp on the nialring wire 'from inside the boa..

could be freed frorn the necessary aniount of its water content by pressure only. g Such pressure was applied as atmospheric pressure the flat boxes followed by mechanical pres sure at the couches and pressen ylta atnaos aheric pressure at the was produced by evacuating the dat bones over which mthe nialring wire, with its layer of oc ravelle l., dit this point in the machine, at n up to and artly across the lastfdat boit the or steelt bas so large a proportion of water that the water acts as a continuous impervious blanlret through which air can not passD @onsecpient ly as the box beneath evacuated the air u sure downwardly from above., on this blanlreh will have no counteracting rr presser tio, a s content will be .pressed out by l the suction boxes, yllbe remainder, f it is practicable to remove it before pas g to the dryers will be talren out at the couches and presses, mostly at the couches., ln this connection I would refer to ltlillspaugh ent 1,025,822, granted lll/lay '7, i912. 'llhis patent discloses in detail the use and operation of the suction roll as a couch. llt also discloses fully the operation of removing water by entrainment as contrasted. with removal by presu sure, and the necessity of uniformity of removal, as well as the need of a positive acting and continuously operating evacuating ineans llerlal lto. Matth.

capable of maintaining within the roll a high substantially constant or non-pulsating vacnum. lt is not thought desirable or really necessary to a clear understanding of the present case to repeat, appreciably, in this case what has been set out in detail in that patent9 as to the operation of the vacuum in removing water by entrainnnent.

ln all prior devices the suction roll, when applied to the wet end of the Fourdrinier machine has been substituted for the lower couch. Alt this point the wire changes from upper to lower run and returns toward the A breast roll. lt forms a loop which encloses about one half of the surface of the roll. This ertended surface gives ample opportunity for vacuum action across the entire suction box aren within the roll while at the saine time giving ample surface for friction drive of the suction roll by the making wire. Due to the great and continuous pressure resulting from the vacuum within the roll, the wire is firmly locked or bound to the roll for friction drive.

-`LWhere the wire travels in a straight or substantially straight path no such contact is possible.. 'lhere is no are of the wire to t about and coincide with a corresponding arc of the roll shell. Consequently there is no possibility of an extended area through which vacuum may act on the pulp layer.

ln view of the facts above set forth, the universal practice-has been to use a series of boites between the breast roll and suction couch roll, the number varying, generally ein three to five according to the particular uinstances of the case. lUnder some ciristances less than three or more than ve ction bones are stationary and have their on areas disposed immediately beneath and parallel with theinalring wire, as is well understood and as will be seen on reference to aforesaid lt/lillspaugh patent. 'lhe wire traveling across these suction bones continuvously subjects successive sections to the vacutil] used in driving the wire simply for the pur.

pose of overcoming this friction. The main objects of the present invention are to avoid these and other objections and provide a device which will adaquately take the place of the flat box in every respect, while at the same time being capable Vof use regardless of deof vacuum-capable of use with either gigli or low vacuum. A further object is to provide a device which will greatly reduce the power necessary for driving the wire and, through it, the suction roll.

l perforations.

In order to more clearly disclose the con` struction, operation and use of the invention,h

reference should be had to the accompanying drawings forming part of the present application. Throu hout the several figures of the drawings, like reference characters designate the same parts in the different views.

Fig. 1 is a diagrammatic side elevation of the wet end of a Fourdrinier with invention ap lied.

ig. 2 is a vertical longitudinal cross section on line 2-2 of Fig. 3, looking in the direction of the arrow, also showing the supvors;

Fig. 3 1s a lateral vertical cross line 3 3 of Fig. 2;

Fig. 4.is a top plan view of the operative sufti'on opening from the suction box of the ro l;

Fig. 5 is a top plan view of a fragment of the shell flattened out as a plate to show countersunk and staggered arrangement of section on Fig. 6 is. a diagrammatic end view of the invention, with a short section of wire, with water seal indicated in detail.

Referring to the drawings in detail, 1 indicates a cvlindrical suction tube closed at one end and adapted to have its opposite end connected to any suitable suction means capable of continuously maintaining a high constant vacuum. This tube is adapted to be made fast, at its opposite ends to the side frame members of the wet end by suitable clamps, collars or the like 2. About this box is revolubly mounted a small diameter suction roll shell 3 which is centralized on tube 1 by spacing blocks 4 and strip 5. The blocks 4 are short, in all directions and act purely as spacers and bearing members for the free running travel of shell 3 about tube 1. The

strip 5, on the other hand, while acting as a spacer, also provides a suction passage from the tube 1 to the perforations of the shell 3. Preferably the slot 7 is continuous through strip 3 and acts as a part of and continuation of a corresponding slot through the-tube 1.

The slot in -tube 1 may be either continuous or interrupted and the strip 5 may be seated on or keyed in the tube 1 at intervals along the slot of the tube, as will be clearly understood. There are, obviously, various ways of securing these parts together in operative relation, only one of which has been illustrated, by way of example.

Within the roll there is, of course, a certain amount of water at all times during operation. With the hard bearing surfaces of the lignum vitae .blocks and strip this acts as a lubricant to give a free running bearing surface, the shell 3 rotating freely about the tube 1 over the en aging surfaces.

Suitable stop co lars 6 are provided on' the tube l at opposite ends of the shell 3 to prevent lengthwise movement of the shell.

The shell 3 is of small diameter, light weight, and has small bearing surfaces well lubricated. Consequently, very little power is required. Suction through the slot 7 will act to create such a difference in pressure between inside of roll and top of Wire that the wire will be tightly pressed against the roll face to provide a frictional drive. Very little power will be necessary to revolve the roll, as previously indicated. All drag on the wire and all frictional wear will be completely eliminated, as the contacting roll and Wire surfaces will travel freely, at the same rate, and

in the same direction. Theoretically, there is only a line contact between the shell and wire. The wire is flexible and carries a considerable load of stock. Necessarily, in practical use, as the wire rests upon the roll it will to a slight extent adapt itse f to the curvature, so that the theoretical line-contact will become somewhat enlarged. It will, instead, become a narrow7 strip from end to end of the roll. The large water content of the/stock as it passes over the roll considerably increases the effective width of this contact by ca illary attraction. The shallow, substantia 1y triangular spaces between the shell and wire will be ke t filled with water or water sealed so that t e suction will not be broken, even though the wire is not looped around the roll, as is the case with the suction couch. This water seal is indicated clearly in Fig. 6 at 8. It will be readily understood that such seal is somewhat modified by the moving parts. On the side from which the wire comes, for instance, the approach of the wire and roll will tend to counteract capillarityto a certain extent and slightly shorten the triangle at that side, while the opposite effect will exist on the other side, all as clearly indicated in Fig. 6.

While the invention has been shown as takaol ing the place of the suction boxes, it is equally clear that it may be substitued for the rst guide rollthe one nearest the couch. In that case, as will be readily understood, there will be a slight actual arc of contact between shell and wire as the roll will be in the angle where the Wire starts downwardly toward the couch from the horizontal. 4

As is well known, only a very low vacuum, seven inches or less of mercury, is practically maintained on the flat boxes because of the great frictional drag. Vith elimination of that drag a vacuum of twenty (20) inches or more may be maintained, making it possible to use one roll to displace several boxes even though the suction area of the roll is greatly reduced relatively to that of the boxes. In some cases it may be found that the contact betwen roll and wire is not sufliciently certain to rely upon, entirely, for driving the roll. In such cases, the shell may be extended 'at one end or the other and provided with a pulley face, groved or otherwise to receive any suitable form of belt or other flexible driving means, as indicated in dotted line.

The preferred form of slotted stri 5 is shown in Fig. 3. The tube 1 is longitu inally grooved, with dove-tail groove, the bottom of the groove being either perforated or slotted for communication with the inside of the tube. A metal channel plate shaped to slide into the groove and similarly slotted or perforated receives the strip 5, the outer face of which is slotted 'its full length for a part of its radial depth. This longitudinal slot communicates by a plurality of short slots or perforations with the openings throu h the metal channel. Thus the strip may easily and quickly renewed at any time. The contact surface of this strip, as well as that of each of the blocks 4 lis rounded to reduce contact area as much as possible.

It is clear, of course, that antifriction bearings may be used between the tube and shell if desired, but the construction illustrated is the simplest and preferred.

While it has been described with particular reference to use in the wet end of a Fourdrinier in place of the flat boxes or guide roll it will be understod that it may be used as a dummy roll in Fourdriniers and as a drum roll in cylinder machines. It is not thought either necessary or desirable to illustrate either of these latter arrangements as they will be readily understood by any one skilled in the art.

It will be noticed that the openings through strip 5, the channel carrying it, and the wall of tube 1 are of increasing cross sectional area from 1thelouter tcp the inner ends. This form comp ete y avoi s any ossibilit of clogging of the passages by the libres of t e pulp.

Having descrlbed my invention, what I claim and desire to protect by Letters Patent 1s:

1. A suction roll of the character described comprising a suction tube, a perforate shell revoluble on said tube, an element extending longitudinally of said tube and provided with passages establishing communication between the inside of said tube and the perforations of said shell, said element being in free running contact with said shell.

2. In combination with a pulp carrying web, a suction tube, and a perforate shell revoluble on said tube and disposed tangentially relatively to and in contact with said web.

3. In combination with a pulp carrying web, a suction tube and a perforate shell revoluble on said tube and disposed tangentially relatively to and in contact with said web, and means for maintaining concentricspaced relation between said tube and shell.

4. In combination with a pulp carrying web, a revolubly mounted perforate shell in tangential contact therewith, and a suction tube for drawing water from the pulp on said web through said shell at the line of Contact.

5. In combination with a pulp carrying web, a revolubly mounted perforate shell in tangential contact therewith and having a Water seal area extending to both sides of said contact, and a suction tube for drawing Water from the pulp on said web through said shell at the line of contact within the area of said water seal.

6. A suction roll of the character described .comprising a suction tube provided with a longitudinal groove having a plurality of openingscommunicating with its interior, a strip seated in said groove and provided with passages therethrough and communicating with the aforesaid openings, spacing blocks carried by said tube, and a perforate shell revoluble about said tube and in free running contact with said strip and said blocks.

7. A suction table roll comprising a perforate revoluble shell and a suction tube within said shell and provided with a narrow longltudinal slot in communication with the perforations of said shell.

8. A suction table roll comprising a suct1on tube provided with a strip having a narrow longitudinal slot, a perforate shell revoluble about said tube and in tangential con,- tact with said stri along said slot.

9. A suction ta le roll comprising a suctlon tube provided with radial spacing elements lone of which is slotted and a perforate shell revoluble about said tube and in longitudinal contact with said slotted spacing element along the line of the slot therethrough.

Signed at Sandusky, Ohio, this 23rd dayv of March, 1928. y

HILAND R. FARNSWORTH. 

